#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

class Solution
{
    vector<int> ret;
    vector<int> index;
    int tmpNum[500010];
    int tmpIndex[500010];
public:
    vector<int> countSmaller(vector<int>& nums)
    {
        int n = nums.size();
        ret.resize(n);
        index.resize(n);
        for(int i=0; i<n; i++)
        {
            index[i] = i;
        }
        mergeSort(nums, 0, n-1);
        return ret;
    }

    void mergeSort(vector<int>& nums, int left, int right)
    {
        if(left >= right)
            return;
        int mid = (right+left)/2;
        mergeSort(nums, left, mid);
        mergeSort(nums, mid+1, right);

        int cur1 = left, cur2 = mid+1, i = 0;
        while(cur1 <= mid && cur2 <= right)
        {
            if(nums[cur1] <= nums[cur2])
            {
                tmpIndex[i] = index[cur2];
                tmpNum[i++] = nums[cur2++];
            }
            else
            {
                ret[index[cur1]] += right-cur2+1;
                tmpIndex[i] = index[cur1];
                tmpNum[i++] = nums[cur1++];
            }
        }
        while(cur1 <= mid)
        {
            tmpIndex[i] = index[cur1];
            tmpNum[i++] = nums[cur1++];
        }
        while(cur2 <= right)
        {
            tmpIndex[i] = index[cur2];
            tmpNum[i++] = nums[cur2++];
        }

        for(int j=left; j<=right; j++)
        {
            nums[j] = tmpNum[j-left];
            index[j] = tmpIndex[j-left];
        }
    }
};